LAFAYETTE, Ind. - An 18-year-old Lafayette man has been arrested after he admitted to beating his 17-day-old son, police said.

Brendan Bell had been caring for the newborn Sunday when a relative visited and noticed injuries on the infant's head, police said.

The newborn was taken to a Lafayette hospital and then transferred to Riley Hospital for Children at Indiana University Health in Indianapolis.

Bell later admitted to police that he had struck the child, who was in a car seat at the time, in the head with an open hand multiple times, police said.

Bell was arrested on preliminary charges of battery causing serious bodily injury and neglect.

The infant was last listed in critical condition.